Arrested members of an ISIS-linked cell in Indonesia were planning attacks on government buildings, TV stations, and the Myanmar Embassy in Jakarta, police said, adding that the scale of the attack might have been even bigger than 2002 Bali bombing.

“They were helping plan a bomb attack against parliament, the national police headquarters, the embassy of Myanmar and several television stations,” national police spokesman Rikwanto said, as cited by AFP.

He added that the attack planned by Islamic State-linked (IS, formerly ISIS/ISIL) militants could have been even worse that the 2002 Bali bombings.

The attack on the Indonesian resort island of Bali killed 202 people and injured 200 more, mostly foreigners. Jemaah Islamiyah, a Southeast Asian militant Islamist terrorist group, linked to the Taliban and Al-Qaeda, was reportedly responsible for the attack. Several of the group’s members were convicted on terrorism charges.

Earlier this week, police arrested Rio Priatna Wibawa, 23, at his home in Majalengka regency, West Java province. Officers discovered large amount of bomb-making material which he allegedly planned to use in the attacks. The bombings were reportedly planned to take place in December, though police failed to find out when exactly.

Police also found a black flag, rounds of bullets, and several weapons, including an air rifle and a machete, police spokesman Boy Rafli Amar said, as cited by Reuters. He described the suspect as a “self-taught bomb-maker.”

His two alleged accomplices, all members of Jamaah Ansharut Daulah, a domestic cell affiliated with Islamic State, were arrested on Saturday and Sunday. Jamaah Ansharut Daulah is a splinter cell of the Jemaah Islamiyah group.

Those arrested were identified as Bahrain Agam and Saiful Bahri, AFP quoted Rikwanto as saying. They reportedly donated money to buy explosives and even helped Wibawa set up a home bomb-making laboratory.

In January, Indonesia was rocked by terrorist attacks staged by Islamic State sympathizers. At least four people were killed and 23 others, including foreigners, were injured after militants set off multiple explosions and fired guns near a shopping mall in central Jakarta. The attack took place near a UN information center, luxury hotels, and foreign embassies.